Regarding such a type of thermochromic coloring color-memory material, the applicant has already proposed (for example, see Patent Reference 1).
In a conventional reversible thermal discoloration material, it discolors bordering before and after a discoloration temperature, only one specified state of both states before and after discoloration exists at the ordinary temperature region, and the other state is maintained while a heat or cold necessary for expressing the state is applied but returns to the state of ordinary temperature region when application of the heat or cold is removed, but in comparison with such a type, the aforementioned thermochromic coloring color-memory material can selectively maintain either of the color of lower side than the discoloration temperature and the color of higher side than that, at the ordinary temperature region and can alternately maintain the color by applying a heat or cold as occasion demands, so that it has been applied to various fields such as the fields of thermo-sensitive recording materials, toys, ornaments and printing.    [Patent Reference 1] U.S. Pat. No. 4,720,301